Glyn Davies, the U.S. ambassador to the International Atomic Energy Agency, told Radio Free Europe/Radio liberty that upcoming talks between Iran, the five permanent members of the U.N. Security Council and Germany were an opportunity for Iran.
He said the talks are focused on "the deep concern that countries have and that the IAEA has that Iran is not cooperating sufficiently with the IAEA and is not being sufficiently transparent."
Western allies claim Iran is using its nuclear program to develop the technology needed to produce a weapon, though Tehran denies the allegations.
Davis said in his interview that an Iranian invitation to Russia and China -- but not the United States, Britain, France or Germany -- to tour certain nuclear sites in the country wasn't the same as meeting international obligations.
"From our standpoint, this notion of having a prearranged, all-expenses-paid tour for a few ambassadors here in Vienna, this is not the same thing as cooperating fully and completely with the IAEA," he said.
Talks are set to begin Jan. 21 in Istanbul.